Method of rolling ferrous sheets



Patented Jan. 18, 1938 PATENT OFFICE METHOD OF ROLLING reasons snnn rs Alfred J. Castle, Chicago, lll., assignor to Inland Steel Company, Chicago, Ill., a corporation of Delaware 4 Claims.

My invention relates generally to the manufacture of dull rolled steel sheets produced, by way of example, and preferably, on continuous strip or sheet mills and involving hot rolling and 5 cold rolling operations, the present application being a division of my pending application for United States Letters Patent Serial No. 695,721, filed October 28, 1933.

As a preface to the following, it may be stated that where the article to be made from the sheet requires a deep-drawing operation, as for example in the case of the manufacture of automobile bodies, it'is necessary, in order that the sheet properly draw in the dies and that scoring of the sheet by slippage in the dies be avoided, that the surfaces of the sheet be in a somewhat roughened condition producing a dull or mat appearance, as distinguished from a highly polished condition. On the other, hand, it is necessary particularly where the article to be formed from the sheet is to be provided with coatings presenting highly polished like surfaces, as in the case of duco coatings, that the depressions in the surface of the sheet be of such minuteness that 5 the coating will be sufiiciently smooth to present the desired high gloss finish. v

While dull surfaced sheets may be produced in accordance with methods and by apparatus as ing and cold rolling operations, by eliminatingcertain operations hithertomequired for the manufacture of sheets similar thereto; to produce sheets, having the desired dull or mat finish, on 4 the mill in the skin-rolling operation after the annealing of the sheets and without requiring the pickling of the sheets prior to the annealing operation which follows the -cold rolling operation; and other objects as will be manifest from the following description.

In accordance with my invention the finishing roll by which the dull or mat finish is to be produced is provided of a scleroscope hardness over 70, preferably about 80, and its working face is eroded, by abrasive or chemical action, to produce thereon, in relief, the pattern which, when imprinted or embossed on the sheet, will cause the sheet to present the desired dull or mat finish.

An example of one kind of roll which may be used in accordance with my invention is a roll of hardened cast steel of a scleroscope hardness as above stated with its working face of substantially uniform hardness throughout and of substantially uniform finely grained structure, such surface being eroded, as for example, by means of an extremely fine abrasive blasted against the roll, to produce the desired mat pattern thereon in relief.

Such a roll would contain, in addition to the normal elements of iron, carbon, phosphorus, sulfur, silicon, and manganese, one or more of the following alloying elements: Nickel, chromium, molybdenum, vanadium, and tungsten, the function of which is to refine the structure and harden the roll.

By way of example the analysis (by weight) of such a roll may be approximately as follows:

Iron, of an amount constituting the balance of the composition.

The nickel element in such composition is more or less immaterial, but when included, it is desirable that it not exceed .20.

In the producing of such a roll the roll, after the casting thereof, would be subjected to a forging operation and thereafter to such heat treatment as to develop the desired hardness of the roll, the working face of the roll then being subjected to the abrading action of an extremely fine abrasive, as for example sand of the order of mesh, to produce on the Working surface the desired mat pattern in relief.

Another example of a roll which may be used is a roll of ferrous composition of a scleroscope hardness over 70, preferably about 80, with its working face of fine dendritic structure, such surface being differentially eroded either by means of a fine abrasive or by chemical etching material.

Such a roll would contain,'in addition to the normal elements of iron, carbon, phosphorus, sulfur, silicon and manganese, one or more of the following alloying elements: Nickel, chromium,-

molybdenum, vanadium and tungsten, the function of which is to refine the dendritic structure analysis (by weight) of such a roll may be 2 w and harden the roll. By way of example, the

approximately as follows:

Iron, of an amount constituting the balance of the composition.

The tungsten element in such composition is more or less immaterial, but when included it is desirable that it approximate about 1.00%.

In the producing of such a roll the roll cast from the above composition would be subjected to a chillingaction to harden the surface thereof to produce a scleroscope hardness of over '70, preferably about 80, and the working face then differentially eroded to produce thereon in relief the desired mat pattern either by mechanical abrasion orchemical etching.

The mechanical abrasion of the roll may be eifected by subjecting it to the abrading action of an extremely fine abrasive, as for example sand of the order of 80 mesh, applied as a blast. The chemical etching of the roll maybe effected as for example by subjecting it to the action of an approximately 10% nitric acid aqueous solution.

As will be understood, the abrasive operates to cut away, and the etching solution operates to eat away, the softer portions of the metal forming the working face of the dendritic roll, leaving in relief the harder portions thereof which define the fine dendritic pattern of the structure causing the working face of the roll to present the desired mat pattern in relief.

Referring to the use of the rolls in connection with the production of sheets on a continuous strip or sheet mill and involving the hot rolling and cold rolling operations and subsequent annealing operation as above referred to, it has been discovered that by utilizing such rolls in the skinrolling operation after the annealing of the sheet. in place of the rolls commonly used in such operation and by which a highly polished sheet is produced, the desired dull or mat finish on the sheet, which it is the object of myinvention to produce, may be produced by a single pass reduction by the rolls, the resultant sheet being of such mat'surface finish as not to require subsequent pickling.

In this connection it may be stated that I have found in practice that another material than that above mentioned and suitable for eroding the working face of the roll of either the dendritic or non-dendritic type, is iron oxide such as that produced by the hot rolling operation, and that the action of producing the desired mat working face on the roll may be obtained by running, through the rolls, hot rolled sheets with the iron oxide or scale thereon.

While I have described rolls of certain compositions and treated in certain ways and have described the use of certain rolls in connection with certain rolling operations and referred to certain apparatus, I do not wish to be understood as intending to limit my invention thereto, as the composition of the rolls and their treatment may be varied, as also the method involving their use and the apparatus in which they are used, without departing from the spirit of my invention.

What I claim as new, and desire to secure by Letters Patent, is:

1. The method of surfacing ferrous I sheets which consists in subjecting their surfaces in cold condition to the rolling action under pres sure, of a metal roll of a scleroscope hardness over and presenting a mat working face.

2. The method of producing ferrous sheets having a. mat surface which comprises passing the sheets in cold condition between rolls under pressure having a surface scleroscope hardness of at least 70 with mechanically produced microscopic sharp crests supported at extended bases thereon.

3. The method of rolling ferrous sheets which comprises cold rolling the sheets, annealing the sheets after the cold rolling, and skin rolling the annealed sheets by subjecting surfaces thereof to I the rolling action, under pressure, of a metal roll of a scleroscope hardness over 70 and presenting a mat working face.

4. The method of rolling ferrous sheets which comprises cold rolling the sheets, annealing the sheets after the cold rolling, and skin rolling the annealed sheets by subjecting surfaces thereof to the rolling action, under pressure, of a metal roll of a scleroscope hardness over 70 and presenting a mat working face of the order produced by the abrading action of fine particles of abrading material of about mesh. I

' ALFRED J. CASTLE. 

